set 4 MCQ Questions & Answers Detailed Explanation

Question : 1

In an n-type silicon, which of the following statement is true?

a) Electrons are minority carriers and pentavalent atoms are the dopants.

b) Holes are minority carriers and pentavalent atoms are the dopants.

c) Electrons are majority carriers and trivalent atoms are the dopants.

d) Holes are majority carriers and trivalent atoms are the dopants.

Question : 2

A compass which is allowed to move in a horizontal plane is taken to a geomagnetic pole. It

a) will stay in any position

b) will stay in north-south direction only

c) will stay in east-west direction only

d) None of these

Question : 3

Consider the following statements regarding electric fuse wire:

1. It has low melting point.
2. It has very high specific resistance.
3. It is connected in parallel with the electric circuit.

a) 1 and 2

b) 1 only

c) 1 and 3

d) 2 and 3

Question : 4

Transformer is used for

a) To step up DC voltages

b) Converting AC into DC

c) Converting DC into AC

d) To step up or step down AC voltages

Question : 5

Refractive index of an optical medium changes with

1. the nature of the medium.
2. the change in the angle of incidence of the ray.
3. colour of the incident ray.

a) 1 and 2 only

b) 1 and 3 only

c) 2 and 3 only

d) 1, 2 and 3

Question : 6

Gases are good conductors of electricity at

a) low pressure

b) low temperature

c) high pressure

d) high temperature